In the past, various instruments were developed for taking voltage and resistance measurement readings and providing their corresponding digital values on a numeric display. To use these instruments, it was necessry for an operator to visually locate the point at which the measurement was to be taken on a circuit, hold the probe of the instrument against the proper point, and look at the digital display on the meter while holding the probe against the proper point on the circuit. In practice, this procedure proved to be extremely fatiguing and error prone because the mere turning away to look at the instrument would often cause the probe to slip from the proper point.
One solution to this problem has been to provide a probe with a push button switch which would allow the operator to touch the desired point, activate the push button and thus hold the reading on the instrument. This allows the operator to devote full attention to the probe until the reading was complete. However, this approach requires a special probe and a number of components in the instrument which are costly extras when this feature is not desired. An approach has long been desired which would allow an instrument to sense when a reading is being taken and to tell the operator when the reading is complete. Heretofore, no method has been developed for achieving this result.
With the availability of inexpensive speech providing integrated circuit chips, it would be desireable to implement a talking instrument which would tell the operator when a reading has been made. At present, the only approach without a push button probe would be to have the instrument talk to provide all the readings which appear on the display. However, this would be very distracting to an operator and may lead to mistakes in taking the readings since the instrument will be taking continuously.
This speech ability would primarily augment the display.